Ember-cli-typescript: Use `prepack` and `postpack` rather than `prepublishOnly` and `postpublish`

[oliverlangan]

As an app or addon publisher, I want my type definitions created in prepack so that I can use a non-standard publishing mechanism.

According to the npm scripts documentation, prepublishOnly only runs on npm publish (and presumably yarn publish), but our CI/publish environment uses neither.

I believe it would be more flexible to use prepack instead of prepublishOnly; and in the interest of making it symmetric, I suggest we also use postpack instead of postpublish.

[chriskrycho]

Thanks for filing this—we'll definitely consider it!

[chriskrycho]

Cc. @chancancode @dfreeman @jamescdavis @hjdivad

[dfreeman]

IIRC we originally went with prepublishOnly/postpublish because Yarn didn't trigger prepack and postpack during publish, so that was our only practical lifecycle hook that would work consistently between Yarn and npm.

While Yarn 1 still plays a bit fast and loose compared to Yarn 2 and npm in terms of when it executes lifecycle scripts, it _does_ look like prepack and postpack trigger correctly during publish in recent Yarn 1.x releases, so this change seems reasonable to me.

For both npm and Yarn 2, I believe this would also make installation from git remotes work properly without requiring any special effort from addon authors, but that's one area where Yarn 1 is still divergent from the other managers in the ecosystem.

[hjdivad]

FWIW we use prepack / postpack at LinkedIn to support custom publishing. It sounds very similar to what @oliverlangan's setup is.